It is known in the art relating to fuel injectors to have a separate valve seat positioned proximate a valve body. In this type of injector arrangement, the valve seat and the valve body are arranged so that that the valve seat is located in a proper operative position in the fuel injector. The connection between the valve seat and valve body should fixedly secure the two components together, as well as, provide a hermetic seal that prevents fuel leaks.
It is believed that the connection between the valve seat and the valve body can be accomplished by different techniques. One known technique is a weld connection. In this arrangement, the valve seat is welded to an end of the valve body in such a fashion that the weld secures the valve seat within an end of the valve body and forms a hermetic seal between the valve seat and the valve body. Another known technique is the crimp/elastomer connection. In this arrangement, the end of the valve body is crimped around the valve seat to secure the valve seat within an end of the valve body. To ensure that a hermetic seal is achieved when the crimp arrangement is employed, an elastomeric member, such as an O-ring, is installed between the valve seat and the valve body.
In a direct injection application, the injector is required to operate in an environment of higher pressures and temperatures than a non-direct injection installation, such as, manifold injector installations. It is believed that the known connection techniques may not endure direct injection operative conditions over prolonged periods of time. The weld connection between the valve seat and the valve body does not provide a failsafe valve seat and valve body connection in the event of weld failure during prolonged operation. Catastrophic failure of the engine could result when the weld connection fails and valve seat enters the engine cylinder. It is also believed that the elastomer in the crimp/elastomer connection between the valve seat and the valve body will deteriorate during prolonged use in a direct injection application.